src/msw/textmeasure.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/textmeasure.cpp
   3 // Purpose:     wxTextMeasure implementation for wxMSW
   4 // Author:      Manuel Martin
   5 // Created:     2012-10-05
   6 // RCS-ID:      $Id:
   7 // Copyright:   (c) 1997-2012 wxWidgets team
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // for compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #ifdef __BORLANDC__
  23     #pragma hdrstop
  24 #endif
  25
  26 #include "wx/msw/private.h"
  27
  28 #ifndef WX_PRECOMP
  29     #include "wx/window.h"
  30     #include "wx/font.h"
  31 #endif //WX_PRECOMP
  32
  33 #include "wx/private/textmeasure.h"
  34
  35 #include "wx/msw/dc.h"
  36
  37 // ============================================================================
  38 // wxTextMeasure implementation
  39 // ============================================================================
  40
  41 void wxTextMeasure::Init()
  42 {
  43     m_hdc = NULL;
  44     m_hfontOld = NULL;
  45
  46     if ( m_dc )
  47     {
  48         wxClassInfo* const ci = m_dc->GetImpl()->GetClassInfo();
  49
  50         if ( ci->IsKindOf(wxCLASSINFO(wxMSWDCImpl)))
  51         {
  52             m_useDCImpl = false;
  53         }
  54     }
  55 }
  56
  57 void wxTextMeasure::BeginMeasuring()
  58 {
  59     if ( m_dc )
  60     {
  61         m_hdc = m_dc->GetHDC();
  62
  63         // Non-native wxDC subclasses should override their DoGetTextExtent()
  64         // and other methods.
  65         wxASSERT_MSG( m_hdc, wxS("Must not be used with non-native wxDCs") );
  66     }
  67     else if ( m_win )
  68     {
  69         m_hdc = ::GetDC(GetHwndOf(m_win));
  70     }
  71
  72     if ( m_font )
  73         m_hfontOld = (HFONT)::SelectObject(m_hdc, GetHfontOf(*m_font));
  74 }
  75
  76 void wxTextMeasure::EndMeasuring()
  77 {
  78     if ( m_hfontOld )
  79     {
  80         ::SelectObject(m_hdc, m_hfontOld);
  81         m_hfontOld = NULL;
  82     }
  83
  84     if ( m_win )
  85         ::ReleaseDC(GetHwndOf(m_win), m_hdc);
  86     //else: our HDC belongs to m_dc, don't touch it
  87
  88     m_hdc = NULL;
  89 }
  90
  91 // Notice we don't check here the font. It is supposed to be OK before the call.
  92 void wxTextMeasure::DoGetTextExtent(const wxString& string,
  93                                        wxCoord *width,
  94                                        wxCoord *height,
  95                                        wxCoord *descent,
  96                                        wxCoord *externalLeading)
  97 {
  98     SIZE sizeRect;
  99     const size_t len = string.length();
 100     if ( !::GetTextExtentPoint32(m_hdc, string.t_str(), len, &sizeRect) )
 101     {
 102         wxLogLastError(wxT("GetTextExtentPoint32()"));
 103     }
 104
 105 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 400)
 106     // the result computed by GetTextExtentPoint32() may be too small as it
 107     // accounts for under/overhang of the first/last character while we want
 108     // just the bounding rect for this string so adjust the width as needed
 109     // (using API not available in 2002 SDKs of WinCE)
 110     if ( len > 0 )
 111     {
 112         ABC widthABC;
 113         const wxChar chFirst = *string.begin();
 114         if ( ::GetCharABCWidths(m_hdc, chFirst, chFirst, &widthABC) )
 115         {
 116             if ( widthABC.abcA < 0 )
 117                 sizeRect.cx -= widthABC.abcA;
 118
 119             if ( len > 1 )
 120             {
 121                 const wxChar chLast = *string.rbegin();
 122                 ::GetCharABCWidths(m_hdc, chLast, chLast, &widthABC);
 123             }
 124             //else: we already have the width of the last character
 125
 126             if ( widthABC.abcC < 0 )
 127                 sizeRect.cx -= widthABC.abcC;
 128         }
 129         //else: GetCharABCWidths() failed, not a TrueType font?
 130     }
 131 #endif // !defined(_WIN32_WCE) || (_WIN32_WCE >= 400)
 132
 133     *width = sizeRect.cx;
 134     *height = sizeRect.cy;
 135
 136     if ( descent || externalLeading )
 137     {
 138         TEXTMETRIC tm;
 139         ::GetTextMetrics(m_hdc, &tm);
 140         if ( descent )
 141             *descent = tm.tmDescent;
 142         if ( externalLeading )
 143             *externalLeading = tm.tmExternalLeading;
 144     }
 145 }
 146
 147 bool wxTextMeasure::DoGetPartialTextExtents(const wxString& text,
 148                                             wxArrayInt& widths,
 149                                             double WXUNUSED(scaleX))
 150 {
 151     static int maxLenText = -1;
 152     static int maxWidth = -1;
 153
 154     if (maxLenText == -1)
 155     {
 156         // Win9x and WinNT+ have different limits
 157         int version = wxGetOsVersion();
 158         maxLenText = version == wxOS_WINDOWS_NT ? 65535 : 8192;
 159         maxWidth =   version == wxOS_WINDOWS_NT ? INT_MAX : 32767;
 160     }
 161
 162     int len = text.length();
 163     if ( len > maxLenText )
 164         len = maxLenText;
 165
 166     int fit = 0;
 167     SIZE sz = {0,0};
 168     if ( !::GetTextExtentExPoint(m_hdc,
 169                                  text.t_str(), // string to check
 170                                  len,
 171                                  maxWidth,
 172                                  &fit,         // [out] count of chars
 173                                                // that will fit
 174                                  &widths[0],   // array to fill
 175                                  &sz) )
 176     {
 177         wxLogLastError(wxT("GetTextExtentExPoint"));
 178
 179         return false;
 180     }
 181
 182     return true;
 183 }